A forced induction system such as a turbocharger or supercharger can boost an engine's horsepower without significantly adding weight. By increasing the charge air density in the individual cylinders, additional fuel can be added and a higher combustion pressure is achieved. Often, engines equipped with fuel injection systems utilize feedback from oxygen sensors in the exhaust to determine the appropriate air-to-fuel ratio. As such, when an engine is configured with a turbocharger, the fuel injection system increases the fuel flow to the cylinder relative to the increased air flow from the turbocharger.
The turbocharger converts exhaust flow energy to mechanical energy via a turbine. The turbine drives an intake air compressor via a shaft. The turbine is positioned in the exhaust stream and is driven by the exhaust stream. The intake air compressor compresses air and provides the pressurized air to the engine. Because the turbine is directly driven by the exhaust gas, exhaust gas temperature affects turbine component durability. The turbine can fail when the exhaust temperature is higher than the operating limit for the turbocharger components.